I recently bought a 2004 Fabia (56,000 miles). It runs fine, but a few days ago the engine light came on. The local mechanic checked the car and found error code P0420 (Catalyst System Efficiency Below Threshold) logged in the system; he reset the light and it has not returned.

In looking into this problem, I found the internet site www.p0420.co.uk The site offers what looks like some sort of flow regulator and states that it will resolve the P0420 error.

Has anyone used the product offered at this website? How exactly does it work, and does it indeed solve the problem?

Does anyone know of an alternative solution or product that would resolve the error?

Is anyone aware of what would have caused this error in the first place? Is the catalytic converter on the verge of needing replacement?

Do you do alot of shot journeys in car, if so a good run down motorway might not hurt,

It could also be a number of other things, don't assume cats faulty because of fault code, could be something as simple as a air leak somewhere

Your not curing the problem by spacing the rear probe out thats more for the people running decats

Does this item actually exist and has anyone used it? Looks like a big fat con.

It has been used and does work on cars with a decat but no point on a lower spec fabia might as well get it fixed mine was the cat but checked everything else first

You can get the same effect by removing the probe, blanking the hole, wrapping the probe tip in insulating tape and zip tying it to a convenient bracket. It's cheating, that's all.